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Subject: Re: [PATCH v4 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device()
To:     Nicolin Chen <nicoleotsuka@gmail.com>, thierry.reding@gmail.com,
        joro@8bytes.org
Cc:     vdumpa@nvidia.com, jonathanh@nvidia.com,
        linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org
References: <20201002060807.32138-1-nicoleotsuka@gmail.com>
 <20201002060807.32138-3-nicoleotsuka@gmail.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <b1a195cf-0127-0531-f6d1-835367511f57@gmail.com>
Date:   Fri, 2 Oct 2020 17:22:41 +0300
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02.10.2020 09:08, Nicolin Chen пишет:
>  static int tegra_smmu_of_xlate(struct device *dev,
>  			       struct of_phandle_args *args)
>  {
> +	struct platform_device *iommu_pdev = of_find_device_by_node(args->np);
> +	struct tegra_mc *mc = platform_get_drvdata(iommu_pdev);
>  	u32 id = args->args[0];
>  
> +	of_node_put(args->np);
> +
> +	if (!mc || !mc->smmu)
> +		return -EPROBE_DEFER;

platform_get_drvdata(NULL) will crash.

> +	dev_iommu_priv_set(dev, mc->smmu);

I think put_device(mc->dev) is missed here, doesn't it?

Why sun50i-iommu driver doesn't have this error-checking? Is it really
needed at all?